How to access query params in a policy

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1

I am trying to write a SimpleCheck policy for an update action. How should I access the query parameters inside the policy?

For example:

This is my URL: post/update/:id. I have an update action for this URL. The action below will update the value of the name field of the given post ID.

Action:

update :update_action do
  change set_attribute(:name, "Some value")
end

How should I find the record where the update action has been performed in my policy?

2

You should be able to add an expr policy that checks the record’s value to update.

policies do
  policy action(:update_action) do
    authorize_if expr(attribute_on_record_to_update == true)
    authorize_if expr(attribute_on_record_to_update == ^actor(:id))
  end
end

if you create a simple_check
the context should have the changeset and changeset.data holds the record to update.

3

Thanks for your reply. Yes, I want to write a simple check, but the changeset.data didn’t have the record, instead, it had Ash.Changeset.OriginalDataNotAvailable{reason: :atomic_query_update}

4

can you try adding require_atomic? false to your action definition.

5

Could you open an issue as well, please? I think this might be a bug. If your validation module has no atomic? callback, we should detect that and run the action in non-atomic mode, or at least show some warning/error.

6

https://hexdocs.pm/ash/Ash.Policy.Check.html#c:requires_original_data?/2

7

Don’t know why I was looking at validations :sweat_smile: must have been tired